The present invention relates to an information recording apparatus for recording information on a recording medium such as a DVD, an information reproducing apparatus for reproducing information recorded on a recording medium such as a DVD, and an information distribution system including an information recording/reproducing apparatus for charging for use of information recorded on a recording medium or distributed through a network or by broadcasting.
In recent years, the advance of digital information processing technology and communication technology such as a broadband ISDN, and the development of an advanced information recording medium such as a DVD which realizes a large capacity and high-quality image and sound are progressing. Along with such development of a variety of advanced information transmission means, the circumstances are allowing users to make use of an enormous number of digitized works which are distributed to the users through a network, a recording medium, or the like. These circumstances increase opportunities for copies and alterations without permission of authors or distribution unintended by authors, so copyright holders are anxious about infringement on their benefits.
An important challenge for wiping out such anxiety of copyright holders is the development of a system which allows quick and easy distribution of digitized works and provides a fair digital information usage environment assuming protection by copyright.
A DVD is a large-capacity personal computer medium replacing a CD-ROM, and various applications to movie, music, game, karaoke, and the like can be expected. For popularization of DVDs, inexpensive DVD titles or spread of a rental DVD market is expected. From these viewpoints as well, it is essential to provide an information distribution system assuming protection by copyright of information, i.e., a system based on a concept of charging not for possession of a digitized work recorded on a recording medium such as a DVD but for use of the digitized work.
It is an object of the present invention to provide an information recording apparatus, an information reproducing apparatus, and an accounting apparatus to constitute an information distribution system which allows quick and easy distribution of digitized works and provides a digital information usage environment assuming protection by copyright.
It is another object of the present invention to provide an information recording apparatus for quickly and easily distributing digitized works which are distributed through a network or a recording medium and constituting a digital information usage environment assuming protection by copyright by charging for use of digital information, an apparatus for reproducing the recorded information, and an accounting apparatus for charging for use of information.
According to an aspect of the present invention, there is provided an information recording apparatus comprising an encryption section for encrypting contents information, a license information generator for encrypting at least a license condition referred to limit use of the contents information and a decoding key for decoding the encrypted contents information to generate license information, and a recording section for recording the contents information encrypted by the encryption section and the license information generated by the license information generator on a recording medium.
According to another aspect of the present invention, there is provided an information reproducing apparatus comprising a storage section for storing second decoding key information for decoding license information, a first decoder section for decoding the license information recorded on the recording medium using the second decoding key stored in the storage section, a decision section for deciding, on the basis of a license condition contained in the license information decoded by the first decoder section, whether contents information can be used, a second decoder section for decoding the encrypted contents information recorded on the recording medium using the first decoding key contained in the license information decoded by the first decoder section when the decision section decides that the contents information can be used, and a reproduction section for reproducing the contents information decoded by the second decoder section.
According to the information recording apparatus of the present invention, the encrypted contents information and the license condition of the contents information are in separately recorded on the recording medium. only the information reproducing apparatus having an authentic decoding key for decoding the license information can reproduce the contents information recorded on the recording medium. In addition, since, before decoding, it is always decided on the basis of the license condition contained in the license information whether the contents information can be used, use of the contents information under an illicit use condition is disabled. Therefore, digital information assuming protection by copyright of the contents information can be quickly and easily distributed.
According to still another aspect of the present invention, there is provided an accounting apparatus for charging for use of contents information recorded on a recording medium, comprising an input section for inputting a desired condition for use of the contents information recorded on the recording medium, a fee claiming section for claiming a fee for use of the contents information on the basis of the condition input by the input section, and a recording section for, upon confirming fee payment in response to the claim, recording, on the recording medium, license information containing at least a license condition for limiting use of the contents information recorded on the recording medium on the basis of the condition input by the input section. With this arrangement, for the recording medium on which the contents information and the license information containing the license condition for limiting use of the contents information are recorded, appropriate charging for use of the contents information is enabled. In addition, digital information assuming protection by copyright of the contents information can be quickly and easily distributed.
According to still another aspect of the present invention, there is provided an accounting apparatus for charging for use of contents information through a recording medium on which contents information and encrypted license information containing at least a license condition referred to limit the use of the contents information are recorded, comprising a license information input section for inputting the encrypted license information recorded on the recording medium, a decoder section for decoding the encrypted license information input by the license information input section, a condition acceptance section for accepting a desired condition for use of the contents information, a fee claiming section for claiming a fee for use of the contents information on the basis of the condition accepted by the condition acceptance section, a license information update section for, upon confirming fee payment in response to the claim, updating the license information decoded by the decoder section, on the basis of the condition input by the condition input section, an encryption section for encrypting the license information updated by the license information update section, and an output section for outputting the license information encrypted by the encryption section. With this arrangement, for the recording medium on which the contents information and the license information containing the license condition for limiting use of the contents information are recorded, appropriat =e charging for use of the contents information is enabled. In addition, digital information assuming protection by copyright of the contents information can be quickly and easily distributed.
According to still another aspect of the present invention, there is provided a decision apparatus for deciding, on the basis of encrypted license information containing at least a license condition referred to to limit use of contents information and key information for decoding the contents information, whether the contents information can be used, comprising a key generator for generating a public key used to encrypt the license information and a secret key for decoding the license information at a predetermined timing, the secret key corresponding to the public key, a decoder section for decoding the input license information using the secret key generated by the key generator, a decision section for deciding, on the basis of the license condition contained in the license information decoded by the decoder section, whether the contents information can be decoded, and an output section for outputting key information contained in the license information decoded by the decoder section when the decision section decides that the contents information can be used.
According to the present invention, since the secret parameter for decoding the license information is generated in a decoder unit A at a predetermined timing and used only within a predetermined period, information security for the license information containing the license condition of the contents information and contents information decoding key can be improved.
According to an update apparatus of the present invention, which updates license information on the basis of a request for updating the license information upon receiving at least a newly designated license condition and second key generation information necessary for generating second key information from a decision device for deciding, on the basis of encrypted license information containing at least a license condition referred to to limit use of contents information, encrypted first key information for decoding the contents information, and first key generation information necessary for generating the second key information for decoding the encrypted first key information, whether the contents information can be used, the license condition and the first key generation information are updated, the second key information is updated on the basis of the updated first key generation information and the second key generation information, and the first key information is encrypted using the updated second key information to generate encrypted license information containing at least the updated license condition, the first key information encrypted using the updated second key information, and the updated first key generation information.
According to the present invention, when the license information is to be updated, the license information can be updated while ensuring the information security without supplying the contents decoding key.
According to an update apparatus of the present invention, which updates license information on the basis of a request for updating the license information upon receiving at least a newly designated license condition, second key generation information necessary for generating second key information, and an updated public key from a decision device for deciding, on the basis of the license information containing at least a license condition referred to to limit use of contents information, encrypted first key information for decoding the contents information, and first key generation information necessary for generating the second key information for decoding the encrypted first key information, whether the contents information can be used, the license information being encrypted using a public key, the license condition and the first key generation information are updated, the second key information is updated on the basis of the updated first key generation information and the second key generation information, and the first key information is encrypted using the updated second key information to generate license information containing at least the updated license condition, the first key information encrypted using the updated second key information, and the updated first key generation information, and the generated license information is encrypted using the supplied public key.
According to the present invention, when the license information is to be updated, the license information can be updated while ensuring the information security without supplying the contents decoding key.
According to the present invention, there is provided an information usage apparatus which receives encrypted first key information for decoding encrypted contents information and first key generation information necessary for generating second key information for decoding the first key information and decodes and uses the contents information, wherein second key generation information necessary for generating the second key information for decoding the first key information is held, the second key information is generated on the basis of the second key generation information and the input first key generation information, and the encrypted contents information is decoded using the generated second key information.
According to the present invention, since the decoding key (first key information) of the contents information is input to the information usage apparatus while being kept encrypted, the information security between the device for outputting the first key information and the information usage apparatus can be improved.
According to still another aspect of the present invention, there is provided an information reproducing apparatus for reproducing contents information from a recording medium on which encrypted contents information and license information containing at least a license condition referred to to limit use of the contents information and first key information for decoding the contents information are recorded, comprising an instrument section for measuring a date and time, a decision section for deciding, on the basis of the date and time measured by the instrument section and the license information recorded on the recording medium, whether the contents information can be used, and an information reproduction section for, when the decision section decides that the contents information can be used, decoding and reproducing the contents information recorded on the recording medium using the first key information output from the decision section, wherein information for notifying the decision section of the date and time from the instrument section and the first key information output from the decision section to the information reproduction section are encrypted.
According to the present invention, the security of information to be transferred among the functional units (the instrument section, the decision section, and the information reproduction section) in the information generation device can be improved.
According to still another aspect of the present invention, there is provided an information recording method of recording, on a recording medium on which at least encrypted contents information is recorded, encrypted license information containing at least a license condition referred to limit use of the contents information and a decoding key of the contents information, comprising transmitting information for designating second key information for encrypting first key information for encrypting the license information to a decision device for deciding whether the contents information can be used, receiving, from the portable recording medium, the first key information for encrypting the license information, which is encrypted using the designated second key information, and recording, on the recording medium, license information generated on the basis of a designated license condition and encrypted using the first key information.
According to the present invention, the contents information recorded on the recording medium cannot be normally decoded unless the decision device which has been used to record the license information in the recording medium is not used. Therefore, illicit use of the contents information can be prevented.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinbefore.